By Karolos Grohmann

LONDON (Reuters) - Uzbek gymnast Luiza Galiulina was provisionally banned from the 2012 Olympics on Sunday after becoming the second athlete in two days to test positive for a banned drug, the International Olympic Committee said.

Galiulina provided a urine sample on July 25 that showed traces of furosemide, a diuretic that can be used as a masking agent or for weight loss.

The Uzbek, scheduled to compete in artistic gymnastics, was banned a day after Albanian weightlifter Hysen Pulaku was thrown out following a positive test for an anabolic steroid.

The 20-year-old Galiulina, who also competed at the 2008 Games, will now have to wait for the testing of a second sample.

Should that also come in positive, she would be barred from competing in London and could face a maximum two-year ban as a first-time doping offender.

Furosemide, often sold under the brand name Lasix, can be used to treat high blood pressure, congestive heart failure or edema (swelling caused by excess fluid retention). It has also been used to prevent horses from bleeding through the nose during races.

Over the course of the London Games, the IOC has said it expects to carry out some 5,000 tests - 3,800 urine and 1,200 blood. Anti-doping agencies conducted thousands more in the run-up to the Olympics, nabbing more than 100 athletes in a drive to root out cheaters before the 16-day competition.

(Additional reporting by Kate Kelland; writing by Ossian Shine; Editing by Mark Trevelyan)